1)There is no clear cut way to make workers pass. I only do promotions when they are level 30 and it seems to work more times than it does not.
2)If you are able to do afk activities I would do (and I personally do) cooking for contribution points. Making things like beer or essence of liquor is easy and the by products give a lot of CP EXP. Otherwise I haven't done dailies for CP in a long time, but I always
did the quest chain in Calpheon . I highly recommend cooking if you can.
3)Yes I use wagons for storage. I have a ton of farms and I park one of my wagons by the farm with a ton of seeds. The only downside to this is it counts as a horse, so only the character you took it out of the stable with will be able to see/take things from it.
4)Been awhile since I did the grunil vendor, but every X amount of patches they seem to change the combo to get the best score from the guy. Did they just change the combo or did they actually nerf the amount of points you get? Crafting isn't too bad if you have been collecting black shards. If you don't want to gather the materials for crafting, you could always preorder the armor for a little over the max price. I'm not sure how in demand they are, so you might be able to get away with a low preorder price.
5)No that isn't how getting something to Pri/Duo/Tri works. First you need Hard Black Crystal Shard for armor or Sharp Black Crystal Shard for weapons. Once you have 1 of those you heat it together with either 2 Black Armor Stones or 2 Weapons Stones. That will give you a Concentrated Magical Black Stone Armor/Weapon. You then use that like you would regular Black Stones. So it is much more expensive to try to level something to Pri/Duo.
Also, once you get something to Duo and try to upgrade it to Tri, if you fail you will go back to Pri. Cron stones try and stop that. Basically if you use Cron stones and fail you have a chance of just losing the Black Stone, and a chance of Degrading like normal. So Cron Stones are basically just another form of RNG.
Repairing armor that you have upgraded to yellow does not need the same type and grade to be repaired. So your yellow grunil only needs a green grunil to repair it.
6)I have a bunch of boss alts that I park near bosses I care about. Other than that, I have 1 gatherer that I park where I like to gather. Best advice here is to just get a fast horse with the holy trinity of horse skills (drift, instant acell, sprint). With a fast horse you can get from one side of the map to the other fairly quickly.